Flame detector using a light guide for optical sensing

摘要

A multi-sensor fire detector includes first and second flame sensors which are coupled to an external environment by a rigid, tapered, optical coupling element. An external end of the coupling element has a cured hemispherical shape with a viewing angle approaching one hundred eighty degrees. Processing and control circuits coupled to the sensors make a determination as to the presence of a fire condition.

主权项

1. A detector comprising multiple optical flame sensor assemblies that operate simultaneously comprising:
a one-piece, elongated, rigid light guide having a hemispherical optical input end where light from a flame directly enters the light guide anywhere over the hemispherical optical input end, a tapered body, and an optical output end, wherein the light guide comprises first and second different, optical flame sensor assemblies, each comprised of a distinct optical bandpass filter and a photodiode for dual frequency temperature evaluation of the light from the flame where each sensor assembly responds to an optical, flame related, signal of a respective color frequency of a flame having an orange-yellowish color and light intensity changes at frequencies below 20-30 Hz; and control circuits, responsive to at least outputs from the different sensor assemblies, wherein the control circuits form a ratio of signals from the first and second sensor assemblies to detect the presence of flames of a fire.